<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
  //封装优先级队列
  function PriorityQueue(){

    //  在PriorityQueue重新创建一个类：可以理解成内部类
    function QueueElement(element,priority){
        this.element = element
        this.priority = priority
    }

      //  封装属性
      this.items = []

      //  1、实现插入方法
      PriorityQueue.prototype.enqueue = function(element,priority){
          //   1、创建QueueElement对象
          var queueElement = new QueueElement(element,priority)

          //   2、判断队列是否为空
          if(this.items.length == 0){
              this.items.push(queueElement)
          }else{
              var added = false
              for(var i = 0;i<this.items.length;i++){
                  if(queueElement.priority < this.items[i].priority){
                      this.items.splice(i,0,queueElement)
                      added = true
                      break
                  }
              }
              if(!added){
                  this.items.push(queueElement)
              }
          }
      }

      //    2、丛队列中移除前端的元素
      Queue.prototype.dequeue = function(element){
          return this.items.shift()
      }

      //    3、查看前端的元素
      Queue.prototype.front = function(element){
          return this.items[0]
      }

      //    4、查看队列是否为空
      Queue.prototype.isEmpty = function(element){
          return this.items.length == 0
      }

      //    5、查看队列中元素的个数
      Queue.prototype.enqueue = function(element){
          return this.items.length
      }

      //    6、toString方法
      Queue.prototype.toString = function(){
          var resultString = ''
          for(var i=0;i<this.items.length;i++){
              resultString += this.items[i] + ' '
          }
          return resultString
      }

  }


</script>
</body>
</html>